diff --git a/blogo/fs.go b/blogo/fs/fs.go
similarity index 97%
rename from blogo/fs.go
rename to blogo/fs/fs.go
index 0d78bd3..8db8e66 100644
--- a/blogo/fs.go
+++ b/blogo/fs/fs.go
@@ -13,12 +13,14 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package blogo
+package fs
 
 import (
 	"io/fs"
 )
 
+var ErrNotExist = fs.ErrNotExist
+
 type FS interface {
 	Metadata() Metadata
 	Open(name string) (File, error)
diff --git a/blogo/metadata.go b/blogo/fs/metadata.go
similarity index 99%
rename from blogo/metadata.go
rename to blogo/fs/metadata.go
index 79a5e67..2dc4c8b 100644
--- a/blogo/metadata.go
+++ b/blogo/fs/metadata.go
@@ -13,7 +13,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package blogo
+package fs
 
 import "errors"